58 
[Assembly 
and is often covered by a bluish black coating, said to be the cop- 
per black of Professor Jameson. 
Sulphate of barytes sometimes accompanies the galena, but as 
far as my observation extends, it is by no means abundant at pre- 
sent. 
I should add that the galena from this locality is said to be ar- 
gentiferous. 
Before concluding this report I will only enumerate some of the 
more interesting and useful minerals which I have obtained in ad- 
dition to those already described. 
Marl. — Supposed to be in great abundance on the lands of Mr. 
Van Bergen, near the village of Coxsackie. The specimen which 
I received has a white color, is very friable when dry, and is near- 
ly a pure carbonate of lime. It promises to be of great value for 
agricultural purposes. 
Magnesian marble, — This mineral, so called by Mr. Nuttal, and 
also known by the general name of carbonate of magnesia, occurs 
on Staten Island. My analysis agrees very well with that of Mr. 
Nuttal.* It is crystallized and compact; its specific gravity is 
2.712; it contains carbonic acid, lime, magnesia, and small portions 
of silica and oxide of iron. 
Fluor spar, — I found a new locality of this interesting mineral 
in Morristown, St. Lawrence county. It is crystallized and has a 
fine green color. 
Calcareous spar, — Several interesting localities of this mineral 
exist in the counties of St. Lawrence and Jefferson. At De Long's 
mill, in the former county, it is sometimes obtained in crystals of 
a straw color, which by cleavage, furnish rhombs having nearly the 
transparency of Iceland spar, and exhibiting double refraction. 
On the farm of Dr. Benton, in the Ox Bow in Jefferson county, 
similar crystals are found, having a beautiful rose tint. Some in- 
teresting secondary forms occur near Gouverneur, St. Lawrence 
county. 
Gibbsite,—-! found this rare mineral associated with the hema- 
titic iron ore, in Dutchess county. It has a yellowish white colour, 
* Silliman's Journal, IV. 17. 
